Complementary color blending



June 16, 1953 R: E. PIKE COMPLEMENTARY COLOR BLENDING Original FiledSept. '30, 1948 FIG. I.

PURPLE v CHROMA HUE BLUE GREEN YELLOW IN VEN TOR.

BY Ralph E. Pi/re W Qflw A TTORNE Y.

Patented June 16, 1953 7 2,642,404 7 e COMPLEMENTARY o'oLoR BLENDINGRalph E. Pike, Media, Pa., assignor to E. I. du

Pont de Nemours & Company, Wilmington, Del., a corporation of DelawareOriginal application September 30, I948,';Serial R No. 51,883; Dividedand this'application Sepj tember 24, 1951,'Serial No. 247,9 57

eye' detects. ivalueii is :the iamountof light in a color';jhow.lightor. dark it is, or how nearly tions is opacity in relatively thin films,a property commonly referred to as hiding power. Although desirable insome of its aspects, this opacity limits the appearance of a film ofcoating composition to the colors reflected fromitssurface. In the pastfew years, coating compositions which have a transparent appearance andrelatively low hiding power, but which possess a desirable depth,luster, and metallic appearance, have been very popular, particularly asautomobile finishes. In this case depth does not involve intensity as inthe term deep color. Rather, it means the optical illusion of distanceor thickness characteristic of metallic finishes. The metallicappearance is difficult to describe, but it might be regarded as the.optical sensation resulting from white orblackit-is: Chromaf is thestrength of the color; howstrong (intense) or weak (gray) By the termcomplementarypigment and related expressions, as usedherein, is meant apigment or group of pigments which will substantially neutralize thecolor of the prime-pigment to a true gray or. to a grayish-base of thesame hue as that desired in the finalcolorn U. S. Patent Nos. 2,140,745;2,335,760; and

2,384,579 describe means of accomplishing some degree of transparency innitrocellulose. lacquer and synthetic enamel compositions. Essentiallythese methods'retainthe principal pigment in a state of very finedivision so that its transparent properties may be,utilized,inconjunction the multicolor effect produced by a somewhattranslucent-coating composition partly by the light reflected from thesurface, and partly by the lighttransmitted by the translucent film andultimately reflected by aluminum flakes in. the film.

A coating composition described as being metallic. in appearancepossesses the following char-, acteristics, to. some degree,simultaneously: (1)

An appearance of depth or distance in the film,

.(2) An ability to change color depending 'on'the a maximum of all fourcharacteristics, useful coating compositions are selected on the basisofthe most favorable combination of those characteristics.

In the description of this invention the terms I for the qualities ofcolor will be based upon the definitions given in the Munsell Book ofColor by A. H. Munsell. Hue is the name of a color, as red or greenthefirst characteristic that the with aluminum flakes, to produce theabovementioned desirable metallic appearance. U. S.

Patent 2,140,745 covers the process of flushing 5 pigments from the wetpulp stage directly into uniform dispersion in lacquers without theintermediate steps of drying-and pulverizing the pigment. Whileapplicable to some degree with all pigments, the process is most usefulwith those ordinarily manufactured by chemical precipitation from watersolution. U. S. Patents 2,335,760 and 2,384,579 prepare iron oxidepigments capable of being flushed into lacquer or enamel vehicles sothat the very small primary particles of the pigment do not agglomerateto any marked extent and so-that the nature of the particles is notsubstantially changedfrom their freshly-precipitatedcondition. Thus,durable, lightfast and relatively inexpensive pigments of comparativelyhigh transparency and low hiding power are made available for use as theprincipal, or so-called prime pigmentin lacquers and synthetic. enamelsfor outdoor exposure. In low. concentrations these colloidal hydrated orhydrous ferric oxides impart an amber tinge to the film-formingcomponent of the coating compositions.

In higher concentrations, the color is a translucent gold, brown, orreddish brown. In the actual use of the iron oxides, it has beennecessary and desirable to add to the iron oxide base compositionclosely controlled amounts of'selected relatively opaque tinting ortoning pigments, suitably dispersed in a useful vehicle, to impartopacity or hiding power, at the same time "coloring the composition tothe desired hue. Small quantities of selected flaked aluminum pigmentadded to this mixture increase the value or lightness of the color andprovide the metallic appearance. However, when these hydrous iron oxidebases are shaded by orthodox methods using conventional pigments-black,white, maroon, blue, green and yelloweither of tw things occurs: (1) Solittle shading pigment is used that the hiding power is insufiicient oran amber or brownish tone from the hydrous iron oxide is visible,limiting the color range of finished compositions to browns and olivegreens. (2) So much shading pigment is used that the excellent outdoordurability of the hydrous iron oxide in the coating composition isovercome by the comparatively poor outdoor durability of the shadingpigments, which in most cases arenotably inferior to hydrous ironoxide.in "color-fastness, chalk-resistance, and general resistance to.film deterioration. For instance, excessive amounts of phthalocyanineblue and green pigments, while providing satisfactory light'stability,produce a dull red chalk or. .bronzeiunder normal exposure conditions.flake cause dulling and aluminum chalkingCarbon black and lamp blackpigments, of the low tinting strength type required to maintain lowaluminum concentration, show early dulling and chalking on exposure.

In order to obtainmaximum freedom from aluminum mottling or flooding(heterogeneous pigment pattern in the applied film.) inpracticalmetallic-enamel formuljations, a minimum concentration of. aluminum intheenamel is essential. Uniortunately, brightness and lightness increasewith aluminum content, and the bright colors are currently the mostpopular ones for articles commonly finished withmetallic colors. Thesebright colors can be made by any of the following methods.

A. Use of high aluminum concentration resulting in severe .iiooding ormottling tendencies and early dulling on exposure.

B. Use of a combination of aluminum and nonchalking. opaque whitepigments, which invariably results in a sacrifice .in metallicappearance over alternate A.'

Excessive amounts of aluminum 4 ing automobile exteriors, which possessmetallic efiect to an unusual degree. Another object is to make durablegray lacquers'or enamels without the use of black or white pigments.Still another object is to make a pigmented composition of a specifichueusing a pigment of that hue or an equivalent blend of more than onepigment in only minor portions with respect to the total pigmentpresent- An additional object of this invention is to provide a methodof using the desirable properties of hydrated iron oxide pigments inenamels and lacquers possessing better durability and a wider variety ofhues than heretofore available. Other objects will appear as theinvention is, described.

There; are no. known pigments which individually impart all the desiredproperties discussed above to a synthetic resin metallic enamel, but

parency, low tinting strength, and good durability, capable of beingtinted to the desired hue with relatively minor quantities of light-fasttoning pigments. that are strong (high in chroma), relatively opaque,high in tinting strength, and that preferably but not necessarilypossess good. durability in enamel films.

Accordingly, the purpose of. this invention is to providev improved;synthetic enamels and lacquers which are durable, lustrous, translucentand metallic in appearance. A. further object is to make new durable,relatively, inexpensive colored coating compositions, suitable forfinishby selecting pigments according to the new procedure of the.present invention, pigments which otherwise are undesirable can becombined to produce brilliant, durable beautiful metallic finishes whichare substantially non-chalking,

andx non-fading.

' The objects of this invention are accomplished fundamentally byusingthe hydrous iron oxide pigments described in U. S. Patents 23351760 and22384579 in combination with. one pigment, or a blend of twopigments,relatively-complementary to the iron pigment so that the yellow natureof the latter is substantially neutralized to a truce gray or to agrayish base of the same hue as that desired in the final. color. Then atinting pigment of that ihue, but of higher chroma, or an equivalentblend of two or more pigments, is added to adjustthe colorrof theprodnotto the desired strength, or chroma. A preferred modification is toselect the neutralizing pigment (or pigments) in such a way that it (orone of them) can be used in excess of the required neutralizing.quantity to produce the desired color. This method reducesthe number ofpigments required and simplifiesthe applicationof this invention tocommercial enamel manufacture. Finally, the value or lightness isadjusted by adding flaked aluminum pigment. The resulting compositionpossesses simutlaneously the desired hue, chroma, and value along withthe most favorable combination of the four characteristics of a metallicenamel: depth, apparent color change, high lighting, and polychromaticeffect. While the above description is based on hydrous iron oxidepigments, the same principle is applicable to other prime pigment bases,as will be explained later.

In the attached drawing, Figure 1 shows the three dimensionaldiagramma'tical concept of color characteristics. The vertical axis isvalue (from black to white), the horizontal axis is chroma (from neutralgray at the center to stronger color away'from the center) and theradial or angular location on any given value plane is hue. Figure 2 isa vertical view of the same system, a two dimensional view showing onlyhue and chroma, the qualities most important in this invention. Thenumbered positions on Figure 2 show the approximate hue and chroma ofthe eight pertinent pigments.

It is to be understood that throughout the examples, the pigments are inthe form of mill bases prepared by dispersing the pigment in a suitablevehicle by grinding in a ball-, roller-, pebble-, or buhrstone-mill, byother suitable dispersing methods, or in some cases by the processes: ofU- S; Patents: 2,140,7515. and 2,384,579..

ageant 11 ns-demos:

Hydrous Iron Oxide (Note 1) (U. S.;P. 2.384.579). Rarnapo Lake ofBrilliant Violet l RN (N o Phthalocyanine Blue. "i Phthalocyanine Green.v Chromium Tetrahydroxide (Guig'nets Green). Lightiast Nickel Azo Salt,the nickel complex of the azo dye ebtained bycoupling diazotizedparachloraniline with 2,4-dihydroxyquinoline 3GB ..(.U...S.112,396,327;.Claimv 5) Extra FineAluminum Flake (Notes'l L" r otesl, nFine 1:Aluminum"Flake ((5 0e i 1 Medium Particle Size Channel Ca b LampBlack. Ferrite Yellow Orange Synthetic Red Iron Ox de. 40% Ponsol BlueLake. I Milori Blue (Ferric Ferrocyanide). Precipitated Hydrous IronOxide (W --(U. s. 1=i2,-335,760).- Vat Thioindigoid Dyestufi-IndoMaroon.

" Nor]; l.In al1 the enamel compositions of the examples the percentageof pigment is'on a pigment. solids-basis? ..NOTE 2.Pigment'Zcan-iurtherbe described asan. Aluminum Lining Paste (non=leafing);in"'whi ch s bstantially no flakesare as large as 20 micronsJin'diameter andrsubstantially all .of the fiakesare less than micronsindiometen. a

a ea ,404

1. '2 and 4. In either case, asmall amount of a flaked aluminum pigmentis added. :This lightens the color -to the desired value the metallic:efiect."

The final steps in producing alfinishedenamel are=ireduction :to thedesired pigment to: binder ratio with additional vehicle, "introductionof driers and other modifiersyand' adjustment to T the .desired.viscosity' with suitable solvents;

' blended in proporti'o The method of this invention. for 'pigmenting anenamel possessing hue and chroma, as contrasted with a neutral gray, isdescribed asfollows for a grayish blue metallic enamel. The desired hueand chroma were selected and. are

represented by t epomrzp on Fig.4. "To arrive at 'this hue and chr'ma,pigments 2 and 3am f yielding b1end 21 which is complementary topigment 1. Blend 21 and pigment 1 are mixed in proportions yieldingblend area is composed of flakes with a diameter larger than 20 microns.NOTE 4.This pigment is a lake of dichloro-isodibenzanthrone on bariumrosinate.

mrasiei pigment l'i's a prime or transparent base pigment-composed ofiron oxide in chemical combination with wat r; an example of which isdisclosed in U. S."Patent 2,384,579. Pigments 5 'and'fiarep'rimepigments possessing qualities comparable to prime pigment 1 indurability, 'lightfastne'ss; transparency, and tinting strength. Hencethey are substantiallyf equivalent to pigment #1 in theprinciple ofthisinvention, but. being different in hue and chroma, theyproducedifferent families of colors when substitutedfor' pigment #1. Pigment 16is similar. to 1 but isy prepared according to U. S. Patent 2,335,760.In the claims the term hydrous iron oxide? is in- 'tendedtorefer topigments substantially equivai :lent to those prepared accordingtoeither of the patents just mentioned above; Pigments 2, 3 l

and 4 are tinting o-r toning pigments possessing high tinting strength,-high chroma, lightfastness, and reasonably good outdoor durability.

durable transparent metallic neutral gray without black or white pigmentWillserveas a fundamental example of an automotive enamel ,of this;invention. In this case it desiredto neutralize the hue and chroma ofpigment'l. yet 5 retain a preponderant proportion of pigment 1 g in thefinished enamel in 'order to utilize its -.transparency' and durabilityto an optimum de- 5:

g're'e. Figure 3 is a graphical representation of .the pigmentation.Since there is no known pigment completely complementary to pigment 1,

proportions of 2 and 4 are blended toproduce an intermediate hue 18,which is'substantially complementary to 1. Then blend 18 and pigment. 1

are blended in the proper proportions to produce 2 .19; a neutral graypossessing substantially; no hue or chroma. Pigment 3 might besubstituted for pigments. A blend of 2 and 3, complementary to 1, wouldhave a higher chroma than blend 18 and would require largerproportionsofpigment' 1 toproduce a neutral grayQfI'he enamel thusproduced would possess greater transparency, less hiding power, and adifferentmetallic effect than the same color gray enamel made withpigments 22 whichis on'ane rtension of a straight line connecting 2 and20, -sothat by'adding pigment preached and reached. I

. N hile the theory of producing a durable gray and a grayish bluemetallic enamel have been explained above; the invention will be morecom pletely understood from the examples listed in Table 2, in which theparts are'by weight; The

' examples are largely shown in tabular form for H convenience ofcomparison. The column or row "headings are identified as follows:

Complementary Blend is blend of pigments to produce an improved metallicenamel of a desired color by this invention. U

Conventional, Blends I and II are alternative blends of conventionalpigments commonly used in metallic enamels of th same color as thecorresponding Complementary enamel. Two alternatives are given forcomparative purposes. For instance, color #B Gray is substantially the"same" color. in its three modifications, namely;-

tional IIl- A P/B is-a designation for the ratio of total pigments tosolid vehicle by weight. This refers to the final enaniel produced,using the pigment Complementary;jConventional I, and Conven blends inthe table. I Variations in P/B ratio occur because each pigment isdispersed (or ground) separately with small quantities of liquid vehicleto produce a mill base. For commercial production r reasons, mill-basesdo not. necessarily have the sam P/B ratio. v The following formularepresents a typical baking enamel vehicle'for all of the tabulatedpigmentations which theparts are'by weight:

I 49% linseed oil-China-wood oil glyceryl enamel is variable becauseitis common practice to prepare enamels ata uniform viscosity ratherthan at a constant percent of volatile-solvent.

and contributes to 2; toblend' 22 in small" increments color 20fis ap-.

Therefore-variations occurirom color to color and" often; even betweendifferent batches. of the: same enamel The viscosity of'the bakingenamels was 37 seconds-:4 seconds. in. ;a1?a2l1ln'#-1D An example of afinishedv synthetic resin enamel the above air dryingvehicle'as a basis,is as follows. The parts are by weight. The pigmentaviscosity' cup at 25C. Agsuitable baking schedtion is taken from Complementary Color A,Gray, ule'for theseproduots applied to metal substrates of Table 2: was1 hour at 225 F. iy l The. following formula is a typical air drying g 35 vehicle for illustrating-all of the tabulated pig-- Pi ment Y n 2'167tations in which the'parts are by weight: 10 e men M p 7 i Pigment. 7,Aluminum 1.228 49% linseedoil-China-wood oil glyceryl. 49% linseedoil-China-wood oil glyceryl phthalate resin (solid) 25.59. phthalateresin 24.527 52% linseed oil-glyceryl phthalate resin 52% linseed oilglyceryl phthalate'resim- 2.701

' (solid) 2,82 50% soya oil-China-wood oil penta- 50% soyaoil-China-wood'oil pentaerythv erythritol phthalate resin 6.599

ritol phthalate resin (solid). 6,88 33% China-wood oilphenolformaldehyde 33% China-wood oil phenol iormaldehyde varnish'(solid') 0.392 varnish (solid) 0.41 Drier solution (16% lead) 0.654Drier solution (16% lead) 0.68 20 Drier solution (3% manganese) 0.436Drier solution (3% manganese) 0.46 Drier solution (2%. cobalt) 0.872Drier solution (2% cobalt)' 0.91 Hydrocarbon solvent (volatile): 59.723Hydrocarbon solvent (volatile) 62.25 a I p I 100.000 I I 7 10009 In allof the '8' basiccolors of Table 2 (A-H), --The final volatile solventcontent varied as the Complementary modification possessed betdescribedunder the baking vehicle. The vister application properties, metallicappearance, cosity of the air drying enamels was the same or outdoordurability, than the two corresponding as for the baking enamels.Conventional enamels. In substantially all in- TABLE 2 Metallic:Enamelflomposltions.

. Complementary Blend' ConventionoLBlend I Conventional Blend II MatchedColor 4 Pigment Pigment Pigment P/B Ra- P igmvru ns, p i

no No Color 3 g w No. Color 5 w No. Color gig.

jm fl 11 (iIXBIaCk-H'HQ 301i Gray 92/100 Y; tlifilejijjjj 5% 81/100 {ufiF311;": i9; (7) Aluminum 30, (7)Alumlnum" '4 (4 Green -i 11 f (B) Gray3/ 8; g fifii 5? 1 00 (l 9 0/ (7) Aluminum (a) Blue 1 (3' v o Green-Gray9.4 100{ gfigfg 9.6/100 1137100 30 n Blue-Groyvcun 8.21100 8.9/100 p9.61100 (9 Aluminum; 30 (97 il'uminum 4-4" 10o V 100-- V (a 'Blue 1 1'(11 nisc'k; .Q (E) Gray 8*1/100 $3; @3562: i ii 8101100 .(6 'vgi10w,, ;j8, 7 W

' (9) Aluminum.. '30 (9)':A1uminum 42 V V (a Blue 2 (13 131301: 4 (F)88/100 2%? eiifitiijjj 53 $3 illifiiejjjjj" 5?" 1"Lg/100 (9) Aluminum 30(9) Muminum 100 100 l (5) Green s1 (11 Black 22 (@G y /100 E5; Eifif iBJ/wv 1100- v (8) Aluminum 23- (8) Aluminum; 60L 7 a 100. v I mo (5Green 55 "(my B1ue '.i. ss- (meme .3/ 0 Eflffi t8 0 0 9.8/100- fig-%%ggi:::: p (8) Aluminum l5 (8) Aluminum" l2 (8) Aluminum-. .23 100 1001 Trace.

.methods known to the art.

pigmentation of synthetic resin enamels of substantially the same coloras the'first two lacquers is shown. pigments are absent, and the pigmentcombinations are based on the principles of. this inven' tion. It istobe understood that in the lacquers, as in the synthetic resin enamels,all pigments had been previously dispersed in a suitable vehicle(usually nitrocellulose for the lacquers) by In all compositions blackand white In Table-3, the Synthetic Resin Enamels may Y be made witheither a baking or anair dry vehicle. v

A suitable vehicle for the lacquers. in'Table 3 has the followinganalysis, by weight:

. Percent Cellulose nitrate 17.6

50% cocoanut oil glyceryl pht alate resin 8.8 Dibutyl phthalate 3.6Blown castor oil 2.5 24.3

Butyl acetate Pigment 16, Yellow 1.4 Pigment 4, Green 0.2 Pigment 17,Maroon 0.2 Pigment 8, Aluminum 1.0 Cellulose nitrate 17.1 50% cocoanutoil glyceryl phthalate resin 1 8.6 Dibutyl phthalate 3.5 Blown castoroil Butyl acetate 23.6 Methyl ethyl ketone 10.5 Methyl isobutyl carbinol5.3 Toluene 4.9 Xylene 4.9 Ethyl alcohol 9.8 High solvencynaphtha 6.6

9 1O stances, the Complementary modification was a r I Percent superiorin every respect. In the Complemen- Methyl ethyl ketone 10.8 taryenamels no black or white pigments were Methyl isobutyl carbinol 5.4used, the aluminum pigment content waslower, Toluene 5.1 with oneexception, and thepigment content was 5 Xylene 5.0 predominantlypigments 1, 5 or 6 or a combina- Ethyl alcohol 13.5 tion thereof so thatthe resulting enamels were High solvency naphtha 3.4 superior inapplication properties, durability and r metallic appearance. r 100.0

TABLE 3 Complementary Complementary Blend' Blend NitrocelluloseSynthetic Lacquer Resin Enamel Matched Color Pigment Pigment P/B P/BRatio Ratio No. Color Percent No. Color Percent V (16) Yellow 51.3 (1)74.0 (J) Br a; g gi ijj: 2 2 5;; 2 8 8 Aluminum 36.4 (s) 13. o

' 7 100.0 100.0 (16) Yellow so. 3 (1) 85. 7 (K) Brown /100{ g3 3Pff 2;:1 g; Q} (8) 4.5 (8) 3.1 100.0 100.0 (5) 68.9 V (16) 11.1 (L) Gray"; 113100 (17) 4.2 .(s) 1.4 (8) 14.4

. (16) 50.2 1 (4 12.4 (M) Gray l 8.55/100 (3) 12.7 7) 19.5 (8) Aluminum5. 2

(5) Green (16) Yellow (N) Dark Gray 11.3/100 (l7) Meroon (4) Green (8Aluminum.

(16) Yellow Green figf (8) Aluminum Percent In the claims the termpreponderant as appliedto the transparent prime pigment means that it ispresent inamount greater than any other single pigment. The termtransparent pigment refers to'a pigment which when dispersed in anorganic vehicle'has low hiding power and transparency as distinguishedfrom a relatively opaque pigment with relatively high hiding power. Inthe former case the transparency of the pigment allows the light toreach the aluminum particles giving the film a high metallic brilliancewhereas an opaque pigment would mask the reflection giving a dull,lifeless film.

The aluminum powders used in the compositions of the present inventionare widely available commercially in the form of mineral spirit pastes.They are made in leafing and non-leafing grades and also in fine gradescalled lining pastes or coarser grades called standard pastes. Any grademay be used, but the standard grade which is considerably coarser thanthe linings grade imparts a much greater brilliance to enamel filmsgiving them an unusual apparent depth. For this reason the standardgrade of aluminum paste is preferred in both cellulose derivative andsynthetic resin enamels of this invention where a maximum degree ofreflection is desired.

The proportions of pigments may vary to give a large assortment ofcolors and effects; but in the preferred embodiment of the invention,the prime transparent pigment (A) of the claims may vary between 25% and85.7% by weight of the total pigment in synthetic resin enamels andbetween 11% and 84% for cellulose derivative lacquers.

The relatively transparent complementary pigments (B) and tintingpigment .(C') of the claims may vary in the preferred embodiment from11% to 45% combined insynthetic resin enamels and from 4.7% to "44.6% incellulose derivative enamels.

The aluminum powder (D) of the claims may vary from 3.1% to 3.0%' insynthetic resin enamels and from 4.5% to 36.4% in cellulose derivativelacquers.

The principles of pigmentation for coating compositions with a metallicappearance disclosed in this invention are applicable to all types offilm-forming materials including, (1) all types of alkyd resins madefrom any combination of a polyhydric alcohol and a polybasic acid,unmodified or modified with non-drying oils, semi-drying oils, or dryingoils such as cocoanut oil, soya oil, and linseed oil, respectively; (2)cellulose derivative film-forming agents; (3) vinyl type materials suchas vinyl, acrylic, and al-lyl resins; (4) urea-formaldehyde type resins;(5) melamine formaldehyde resins; (6) phenol formaldehyde .resins andoleoresinous compositions prepared pigments other than violet #2, blue#3, green #4 and maroon I I will be found useful in the practice of thisinvention; and those listed are used It is obvious to one skilled in theart that use-- ful coating compositions can be made within the scope ofthis invention using other prime or transparent base pigments, othertinting pigments, and other grades of aluminum pastes, re-

' sulting in the improvements set forth previously,

although those used in this disclosure are currently preferred becausethe resulting colors are at present the :most popular where metallicenamels are largely usedautomobiles and certain other commercialarticles.

The advantages of the enamels of this invention over conventionalmetallic coating compositions are depth, high-lighting of colors,apparent color change when viewed from different directions or underdifferent light, and polychromatic appearance; and, in :addition tothese, a marked improvement in outdoor durability overconventionalmetallic enamels in gloss retention, color retention, andgeneral film integrity, includin freedom from bronzing, chalking,checking, and cracking. The application properties and resistance toaluminum mottling of the meta'ilic enamels of this invention are equalto, or better than, the duller and less: brilliant conventional metallicenamels and are far superior to conventional products which have hadlarge quantities of aluminum flakes added to enhance the metalliceffect.

It is apparent that many widely different embodiments of this inventionmay be made without departing from the spirit and scope thereof, andtherefore, it is not intended to be limited except as indicated in theappended claims.

This application is a division of my copendin application, Serial No.51,883, now Patent 2,604,414.

I claim:

1. A coating composition adapted to yield a tough, durable finish havinga metallic appearance of great depth and brilliance, comprising avehicle and pigment, said pigment consisting of (A) the nickel complexof the azo dye obtained by coupling diazotized parachloraniline with2,4- dihydroxyquinoline; (B) pigment substantially complementary incolor to the said (A) pigment in amount to yield a gray whenmixedseparately therewith; (C) at least one. colored tinting pigment and (D)finely divided flake aluminum metal.

2. The composition. of claim 1 in which the aluminum flake is relativelycoarse and about 40% of the total aluminum surface area is composed offlakes with a diameter larger than 20 microns.

3. The composition of claim 1 in which the pigment (A) is present inamount between 1.1% and 85.7% by'weight of the total. pigment;comlementary pigment (B) and tinting pigment (C) combined are present inamount between4.7;%

and 45%; and aluminum flake; powder (D) is present in amount between 3.1and-36.4%.

4. The composition of claim 1 in which the vehicle contains a syntheticresin and the pigments are present in amount as follows:

(A) 25% to 85.7% by weight (B) and (c) 11% to 45 (D) 3.1% to 30% (A) 1to 84% by weight 13) and (c) 4.7% to 44.6% (D) 4.5% to 36.4%

6. The composition of claim 1 in which the pigment (B) is composed of aplurality of pi ments, the resulting shade of which is substantiallycomplementary to pigment (A). Y

7. The composition of claim 1 in which th pigment (B) is composed of aplurality of pigments, one of which is in excess of the amount necessaryto produce a color complementary to pigment (A), the said excess beingpigment (C).

8. A process of preparing coating compositions adapted to produce tough,durable finishes having a metallic appearance of great depth andbrilliance, which comprises blending (A) a relatively transparentpigmented composition, the pigment portion of which consists essentiallyof the nickel complex of the azo dye obtained by coupling diazotizedparachloraniline with '2,4 -dihydroxyquinoline; with (B) a pigmentedcomposition in which the pigment is substantially complementary in colorto the pigment of (A) tinting the resulting blend with (C) a colored,pigmented composition and adding (D) flake aluminum metal.

9. The process of claim 8 in which the aluminum'flake is relativelycoarse and about 40% of the total aluminum surface area is composed offlakes with a diameter larger than 20 microns.

10. The'composition of claim 1 in which the pigment (B) is a lake ofdichloroisodibenzanthrone on barium rosinate.

11. The composition of claim 1 in which the pigment (B) comprisesphthalocyanine blue.

12. The composition of claim '1 in which the pigment (B) comprisesphthalocyanine green.

13. The composition of claim 1 in which the pigment (B) is vatthioindigoid dyestuff-indo maroon.

14. The process of claim 8 in which the pigment (B) is a lake ofdichloroisodibenzanthrone on barium rosinate.

15. The process of claim 8 in which the pigment (B) comprisesphthalocyanine blue.

16. The process of claim 8 in which the pigment (B) comprisesphthalocyanine green.

17. The process of claim 8 in which the pigment (B) is vat thioindigoiddyestufi-indo maroon.

RALPH E. PIKE.

No references cited.

1. A COATING COMPOSITION ADAPTED TO YIELD A TOUGH, DURABLE FINISH HAVINGA METALLIC APPEARANCE OF GREAT DEPTH SAID BRILLIANCE, COMPRISING AVEHICLE AND PIGMENT, SAID PIGMENT CONSISTING OF (A) THE NICKEL COMPLEXOF THE AZO DYE OBTAINED BY COUPLING DIAZOTIZED PARACHLORANILINE WITH2,4DIHYDROXYQUINOLINE; (B) PIGMENT SUBSTANTIALLY COMPLEMENTARY IN COLORTO THE SAID (A) PIGMENT IN AMOUNT TO YIELD A GRAY WHEN MIXED SEPARATELYTHEREWITH; (C) AT LEAST ONE COLORED TINTING PIGMENT AND (D) FINELYDIVIDED FLAKE ALUMINUM METAL.